Laminating resins have long been used in conjunction with solid materials, typically those which are thermoset or thermoplastic materials which are reinforced by fibers. Typically, the resins are coated, sprayed, or brushed onto components which are used as panels forming the exterior bodies of vehicles, marine vessels, and other molded articles. Subsequently, the component is subjected to specified conditions such as temperature so as to cure the resin. The laminated resin is useful in that it imparts desirable physical properties to the panel. In particular, the cured resin typically displays adequate strength, toughness, elongation, heat distortion temperature, and chemical resistance properties. Moreover, the resin is desirable in that it provides a finished appearance to the exterior body.
A traditional laminating resin is typically formed from several components including unsaturated polyesters and bisphenol compounds such as difunctional bisphenol-A acrylic esters. The resin also typically includes a volatile monomer diluent such as styrene or vinyl toluene to facilitate employing the resin as a liquid.
The use of volatile monomers, however, have become disfavored due to alleged increased environmental risks. For example, U.S. Pat. No. 5,393,830 to Smeal et al. proposes a laminating resin which employs a reduced amount of styrene so as to meet a specified volatile emission test standard. The resin comprises a polyester resin, ethylene glycol dimethacrylate, vinyl toluene, cyclohexyl methacrylate, and bisphenol-A dimethacrylate.
The use of bisphenol-A dimethacrylate in a laminating resin, however, suffers from various drawbacks. For example, utilizing the bisphenol compound in forming a laminating resin is unduly complex from a processing standpoint in that multiple lengthy steps are needed before achieving the final resin end product. Moreover, the bisphenol-A dimethacrylate material is often one of the more expensive components used in formulating the laminating resin.
In view of the above, it is an object of the present invention to provide a laminating resin composition which utilizes a reduced level of volatile monomer diluent such as styrene.
It is a further object of the present invention to provide a laminating resin exhibiting good end properties which employs relatively less expensive starting material and is produced from a simpler process relative to conventional processes.